Light control for photographic printers



Dec. s, 1927. 1,651,767

N1 B. GREEN LIGHT CONTROL FOR PHOTOGRAPHIC PRINTERS Filed March 5.11925 's sheets-sheet 1 .Z4 5.5

i .j I INVENToR, I //Vegmqr een, BY@ JI. f

ATTORNEYS.

N. B. GREEN LIGHT CONTROL FOR PHOTOGRAPHIG PRINTERS Dec. s, 1927. 1 1,651,767

Filed March 5. 1925 3 'sheets-sheet 2 .El i- FI 5- 28 Z 27 29 2611129 Z5 z 29x27,

INVENToR, v JVewZoN/B Green, BY W02. l f

A TTORNEYS.

Dec. s, 1927. 1,651,767

N. B. GREEN LIGHT CONTROL FOR PHOTOGRAPHIC PRINTERS Filed March 5. 1925 3 Sheets-Shee' .3

"Patented Dec. 6, 1927.`

UNITED STATESI l 1,651,767 PATENT OFFICE.

NEWTON IB. GREEN, OF ROCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COM- PANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

LIGHT CONTROL FOR PHOTOGRAPHIC PRINTERS.

Application led March 5, 19425. Serial No. 13,298.A

This invention relates to photography, and more particularly to photographic printing machines. One object of my invention is to provide a printer with which the light intensity for printing may be varied at will. Another object is to provide a printer in which any lighting arrangement once used may be accurately duplicated at any time. Another object is to provide a printer in `,10 which the individual lamp control members may be moved while the lighting effect is being. watched by an operator. Another object to provide a. printer in which thc lamps may be automatically or manually Y lighted, and other objects will appear herei'nafter from the following specification, the novel features being pointed out in the claims at the end thereof.

It is common practice in making photo- .'20 graphic prints to vary the light intensity by inserting semi-transparent material between the printing lamps and the printing panel. Tissue paper, ground glass or opal glass are the most commonly used materials. It is,

however, diiiicult to reproduce any lighting effect which has been obtained in this manner where the normal lighting over only a portion of the printing panel has been modified. My invention is particularly directed to a light control mechanism by which the light intensity of different areas of the printing panel may be altered and by which any de red 'lighting effect may be repeated at w1 Coming now to the drawings, wherein like reference characters denote like parts throughout:

y Fig. 1 is apart section and part side elevation of a printing machine constructed in accordance with, and embodying one form of my invention;

Fig. 2 is an enlarged elevation of the lamp control box, aportion of the cover plate hav'- ing been broken away.

Fig. 3 is an end elevation of the lamp control box, a portion of the end plate being broken away;

Fig. 4 is a diagrammatic wiring diagram;

Fi 5 is a section on line 5-5 of Fig. 1 showing the main switch mechanism;

Fig. 6 is a diagrammatic showing of a typical negative which requires modified lighting conditions for the printing;

Fig. 7 is a plan view of a film storage envelope which may be marked with the lighting conditions in accordance with my invention;

Fig. 8 is a plan view of anegative marked with the lighting conditions, and

Fig. 9 is a fragmentary section of a nega! tive showing another form of marking, indicating the light conditions used for printing.

I have shown by way of illustration my invention as applied to a photographic printing machine of the type shown in the application of Benjamin D. Chamberlin forphotographic printing machines, Serial No. 12,098, filed Feb. 27, 1925. This machine comprises broadly a table top 10 in which there is a glass printing panel 11 above a. lamp house 12, the corners of the lamp house being formed of angle iron members 13 which form the supporting legs for the table 10. A metal frame 14 extends upwardly from the table top vand carries a plurality of links 15 which, as fully shown in the Chamberlin application, form the operating toggles for the platen sections 16 and 17, these sections being moved to and from the inoperative position shown in Fig. 1 by means of a handle 18 and arm 19, shaft 20 and links, not shown, connecting this shaft with the links 15. Platen section 17 is hinged at18 to the frame 14 upon a shaft 19. A plurality of printing lamps L are mounted in sockets 20 carried by the plate 21v inside ot the lamp house. 'Ihese lamps are designated as L1, L2, La, L4, L5 and L".

In the present-embodiment of my invention, I provide a lamp control mechanism mounted on top of the frame 14 enclosed in a housing 25. This housing is in the form of a box, and as best shown in Figs'. 2 and 3,`

it contains a plurality of rheostats R, each o-f which includes a coil 26. mounted on an insulated tubular member 27. Three of the tubes 27 are preferably supported upon three rods 28 which pass through apertures 29 in the tubes, and hold them in the proper alignment. Each coil .26 is provided with a sliding contact member 29 which is operated through a shaft 30 by means of a knob 31. In order to frictionally hold these Sliding contact members in the desired position, arms 32' are bent from the side of the contact members so as to frictionally engage the cover plate 33. The Contact 29 is spring pressed against the coil 26. On the outside of the cover plate 33, are preferably prov los vided scales 34 which may be graduated into arbitrary units indicating various different light intensities. A pointer 35 carried by the knob 31 moves over this scale as the contact 29 is moved over the coil 26, so that the light setting of the individual lamp may be read from the scale.

Referring to Fig. 4, the lamps L1, L2, La, L4, L's and Le are shown as arrangedin a definite pattern,--that is, in this instance they arearranged in two parallel rows. I prefer to mount the rheostats, designated broadly as R in the same pattern as that of the lamps, so that when an operator looking down through the printing panel desires to alter the light intensity in the lower right hand corner, for instance lamp 6, he may adjust the rheostat Re which is in the lower right hand corner ofthe control box. Each lamp control member is, therefore, arranged in the same relative position as that of the lamp which'it controls.

In Fig. 4 the line wires 40 and 41 furnish "power to the lamps in the following manner: One wire 42 leads to a terminal 43 in each of the rheostat coils 26. The contact- 29 in each case is connected to a wire 44 which leads to one terminal 45 of each of the lamps. The opposite terminal 46 of the lamps is connected to a wire 47 which ends at a switch 48. This switch may be operated by the levers 49 or 50, as will be hereinafter more fully described. It is customary to providea red light, sometimes known as a pilot light, this being shown at 50 connected by means of wires 51 and 52 so as to burn continuously.

Referring to Fig. 5, the main control switch 60 is of the type in which an operating plunger 61 is spring pressed upwardly. Contact is made b depressing this plunger, and this may be one by means of an arm 62 pivoted at 63 to the frame 14 and having a spring 64 tendingto raise the arm in the direction shown by the arrow. The switch 60 may be actuated automatically when the platen is lowered against the printing'panel by means of an arm 50 which is attached to shaft 20, the set screw 51 being adjusted so that the roller 52 will, by depressing cam 53, cause the arm 62 to attuate the switch after the platen has been brought to rest.

The switch may be operated independently of the platen operating mechanism by means of the lever 49 which is attached to a shaft 65 having a handle 66 projecting out to one side of the platen, as isl shown in Fig. l. By rocking this handle a short distance, lever 62 is depressedclosing the circuit by means of the switch 60. This feature is useful because an operator may judge the' effect of different lighting by adjusting the rheostats while looking through the negative.

The operation of my device isas follows:

Assuming that a negative, as shown in Fig. 6, is to be printed," and that the contrast between the dense portion a3 and the transparent portion t is much greater than is desired in the resulting print, the operator turns rheostats R 1, 2 and 3 fully on, and the rheostats R 4, 5 and 6 may be either turned off or turned so that the lamps will burn dimly. This, of course, is an extreme condition, but it is one which nevertheless occurs. If in this setting the desired printing is obtained, the lighting conditions may be recorded in the manner shown in Figs. 7, 8 or 9. For instance, in Fig. 7 the printing data arefmarked on a negative envelope M in which the negative is stored so that if at any times another printing is desired, an exact duplicate of the original may be obtained, by means of ad- ,'ustinor the lam control mechanism in accordance with the printing data marked on the envelope. In Fig. 8 the printing data are shown as being marked on the margin of the negative itself. If desired, the numerals from 1 to 6 inclusive, as shown at S, may be printed upon the margin of the negative with a stamp, and the light intensity designating symbols T may be filled in in ink or with pencil after the fir'st printing is made.

In Fig. 9, I have shown another method of' marking the printing data required for the best results. In this ligure the negative H i is printed with a series of arc shaped scales P which are numbered in accordance with the rheostats on the printer. After obtaining the most suitable lightingV for the negative, an operator may very rapidly 'indicate on the printedscales the required light conditions by making marks Q on the scales to indicate thev setting of the rheostats upon produce certain areas on the printing panelV which are illuminated with greater or less intensity than the major portion -of the printing panel, so that a wide variety of light conditions may be obtained.

vIn the present embodiment of my invention, I have shown my printer as equipped with six printing lamps and rheostats. Of course, the numberl of lamps and lamp controls may be altered to suit the size of the printer andthe conditions under which the printing machine is to be used.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. Ina photographic printingvmachne,

`the scales 34. It will thus be obvious that any lighting condition may be repeated atl the combination with a frame having a printing panel therein, of a platen movable thereover to and from an inoperative position in which it is angularly disposed with respect to the printing panel, lamps posi- .tioned beneath the printing panel, and

means supported by the frame and located above the platen when in its inoperative position for controlling" the light intensity.

2. Ina photographic printing machine, the -conibination /with a frame having a printing panel thereon, of a platen movable thereover to and from an inoperative position in which it is angular-ly disposed with respeetrto the printing panel, a plurality of lamps located beneath the printing panel in a definite pattern, and a plurality of means supported by the frameand located above plurality of indicating devices supported by the frame and located above the platen When in its inoperative position for indicating the brightness of each lam 4. In a photographlc printing machine, thecombination of a printing panel, of a platen movable ther'eover' to and from an inoperative position in which it is angularly disposed with respect to the printing panel, a plurality of lamps-positioned beneath the printing panel, a plurality of rheostats for controlling the brightness of the lamps, and means for indicating the brightness of the printing lamps so located With respect lto the platen that the indicating means may be ,visible in all positions of the platen.

5. In a photographic-printing machine, the eolnbination of a frame having a printingpanel thereon, of a platen movable thereover to and from an inoperative position in which itis angularly disposed with respect to the printing panel, a plurality of lamps arranged in a definite pattern beneath the printingpancl, a plurality of rheostats arranged'in a pattern similar to the pattern of the lamps, and a'plurality of indicating devices supported by the\ frame above the platen when in its inoperative position.

6. In a printing machine, the combination of a frame having a printing panel thereon, ot a platenmovable thereover to and from an inoperative position in which it is angularly disposed With respect to the printing panel, a plurality of rheostats arranged in a pattern similar to that of the lamps, a

pointer on each rheostat, a scale associated with each pointer, the pointers and scales being positioned on the frame of the printing machine to .be visible when the platen is in an operatlve or an inoperative position.

Signed at Rochester, New York this 28th day of February, 1925.

- NEWTON B. GREEN. 

